White light emitting diode

Abstract

According to example embodiments, a white light-emitting diode may be configured to emit white light without a phosphor. According to example embodiments, a white light-emitting diode may include a first semiconductor layer that includes a plurality of hexagonal-pyramid shape nanostructures that protrude upwards from an upper surface of the first semiconductor layer, at least two multi-quantum well layers that are sequentially stacked on the hexagonal-pyramid shape nanostructures; and a second semiconductor layer on the multi-quantum well layers. The at least two multi-quantum well layers may be configured to generate lights having different wavelengths, and white light may be generated by mixing the lights having different wavelengths.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2012-0028416, filed on Mar. 20, 2012, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.BACKGROUND[0002]1. Field[0003]Example embodiments relate to white light-emitting diodes, and more particularly, to white light-emitting diodes that include a nano light-emitting unit having a hexagonal-pyramid type nanostructure and being configured to provide white light without a phosphor.[0004]2. Description of the Related Art[0005]A light emitting diode (LED) may be a high efficiency and / or an eco-friendly light source, and thus, may be used in various devices such as displays, optical communication device, automobiles, or general lightings.[0006]Phosphors may be used to emit white light in a white LED using an LED as a light source. For example, white light may be emitted by exciting a red ...

AI Technical Summary

Benefits of technology

The patent describes a new type of white light-emitting diode that has high internal quantum efficiency and optical extraction efficiency. The diode has a unique structure with nanostructures that emit light with a long wavelength. This structure prevents crystal defects and ensures a simple manufacturing process. The resulting diode emits white light with high efficiency and can be used in various applications.

Problems solved by technology

However, the light-emitting efficiency of a thin film-type InGaN LED becomes low as the wavelength of the thin film-type InGaN LED increases.

In particular, the light-emitting efficiency of the thin film-type InGaN LED may be reduced in a green light wavelength bandwidth due to a lattice mismatch between the thin film-type InGaN LED and a substrate.

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